Avoiding the buildup of stray crop material in the vicinity of the belts and guide shafts of a rotary baler is desirable for many reasons. Generally speaking, positions along the shafts where belts are located side-by-side have a tendency to be self-cleaning in that the two adjacent, moving belts continuously engage errant materials escaping from the baling chamber and forcefully expel such materials from the immediate vicinity of the shafts. At the ends of the shafts, however, there will normally be only a single moving belt working somewhat adjacent stationary structure supporting the shaft, and at this location there is less of a tendency for the stray materials to be expelled from the area.
Furthermore, some of the shafts seem to be more vulnerable than others to buildup. For example, the shafts 58 and 60 of the aforementioned application ride directly upon the upper periphery of the forming bale as part of the belt tensioning apparatus of the baler and tend to collect material more readily than other shafts of the machine.